Voltage regulator and cooling control integrated circuit

ABSTRACT

According to an embodiment of the invention, an apparatus is provided which includes a microprocessor, and a built-in temperature sensor configured to measure a temperature of the microprocessor as a reference temperature. The apparatus further includes external temperature sensors, where at least one of the external temperature sensors is configured to measure the temperature of the microprocessor. The microprocessor is configured to make an external temperature calibration using the reference temperature measured by the built-in temperature monitor. Each of the external temperature sensors is configured to monitor temperature information of a component and provide the temperature information to the microprocessor.

BACKGROUND

1. Field

Embodiments of the present invention generally relate to electronics.More specifically, certain embodiments of the present invention relateto voltage regulation, temperature detection, and temperature control.

2. Description of the Related Art

In computer systems, components, such as a central processing unit(“CPU”) a graphics processing unit (“GPU”), or a memory unit, canconsume power at a high rate during operation. The amount of power thatthe components consume is controlled, in part, by a voltage regulator(“VR”), which maintains the voltage level of the components at aconstant level. The high rate of power consumption during operation cancause the components to produce a large amount of heat. This heat mustbe dissipated in order to keep the components within their safeoperating temperatures. If a component exceeds its safe operatingtemperature, the component may overheat which can lead to performanceinstability, malfunction, or permanent damage.

To avoid component overheating, computer systems can include peripheraldevices that help keep the heat of each component at a safe operationallevel. An example of such a peripheral device is a cooling fan. Acooling fan is a fan, generally within a computer case, that can be usedfor cooling purposes. A cooling fan can draw cooler air into thecomputer case from outside, expel warm air from inside, or move airacross a heat sink to cool a particular component. A computer system canhave one or more cooling fans (or other cooling devices) in order tomaintain a safe temperature for its components.

In order to know when to activate a cooling fan, and to know how muchpower to provide to the cooling fan, a computer system needs to know thetemperature of its components, especially the components that have ahigh rate of power consumption. In order to provide the temperature ofits components, the computer system can include additional peripheraldevices that monitor the temperature. An example of such a peripheraldevice is a thermistor. Another example is a diode. A thermistor ordiode can monitor the temperature of a component, and communicate thattemperature in order to manage safe operation of the component. If acomputer system has multiple components that could potentially overheat,then a computer system can have multiple thermistors (or diodes or othertemperature sensors), one for each component, in order to monitor thetemperature of each component.

Therefore, a computer system may require multiple VRs, temperaturesensors, and cooling fans, where these three types of peripheral devicescan work together to ensure safe operation of its components.Furthermore, these three types of peripheral devices can be connected toeach other using a data bus for adaptive control. For higherreliability, the computer system may need to increase its temperaturemonitor points and intelligent voltage and cooling controllersconfigured to control the VRs and cooling fans, respectively. However,any increase in additional peripheral devices results in an increase inprinted circuit board (“PCB”) space and cost. Thus, it is difficult toobtain high reliability, high efficiency, and low power requirements,without also incurring an increase in PCB space and cost.

SUMMARY

According to an embodiment, an apparatus includes a microprocessor, anda built-in temperature sensor configured to measure a temperature of themicroprocessor as a reference temperature. The apparatus furtherincludes external temperature sensors, where at least one of theexternal temperature sensors is configured to measure the temperature ofthe microprocessor. The microprocessor is configured to make an externaltemperature calibration using the reference temperature measured by thebuilt-in temperature monitor. Each of the external temperature sensorsis configured to monitor temperature information of a component andprovide the temperature information to the microprocessor.

According to another embodiment, a method includes measuring atemperature, and determining whether the measured temperature is higherthan a first threshold. The method further includes, when the measuredtemperature is higher than a first threshold, determining whether aspeed of a cooling fan is less than a maximum speed of the cooling fan.The method further includes, when the speed of the cooling fan is lessthan the maximum speed of the cooling fan, increasing the speed of thecooling fan. The method further includes, when the speed of the coolingfan is equal to the maximum speed of the cooling fan, determiningwhether a voltage generated by a voltage regulator can be decreased. Themethod further includes, when the voltage generated by the voltageregulator can be decreased, decreasing the voltage generated by thevoltage regulator.

BRIEF DESCRIPTION OF THE DRAWINGS

Further embodiments, details, advantages, and modifications of thepresent invention will become apparent from the following detaileddescription of the preferred embodiments, which is to be taken inconjunction with the accompanying drawings, wherein:

FIG. 1 illustrates a block diagram of a voltage regulator and coolingsystem for a server.

FIG. 2 illustrates a block diagram of a voltage regulator and coolingsystem of a notebook personal computer.

FIG. 3 illustrates an example of an application circuit configured tosense temperature at multiple locations using multiple temperaturesensors.

FIG. 4 illustrates an example of a sensing input circuit.

FIG. 5 illustrates a chart which correlates a common mode noise amountwith a temperature sensing error amount.

FIG. 6 illustrates a chart which correlates a leakage resistance amountwith a temperature sensing error amount.

FIG. 7 illustrates a microcontroller unit-based voltage regulator andcooling control integrated circuit, according to an embodiment of theinvention.

FIG. 8 illustrates a temperature sensor and fan control portion of amicrocontroller unit-based control integrated circuit, according to anembodiment of the invention.

FIG. 9 illustrates a voltage regulator control portion of amicrocontroller unit-based control integrated circuit and powersystem-in-packages, according to an embodiment of the invention.

FIG. 10 illustrates a voltage regulator and cooling control methodaccording to an embodiment of the invention.

DETAILED DESCRIPTION

It will be readily understood that the components of the presentinvention, as generally described and illustrated in the figures herein,may be arranged and designed in a wide variety of differentconfigurations. Thus, the following detailed description of theembodiments of a method and apparatus, as represented in the attachedfigures, is not intended to limit the scope of the invention as claimed,but is merely representative of selected embodiments of the invention.

The features, structures, or characteristics of the invention describedthroughout this specification may be combined in any suitable manner inone or more embodiments. For example, the usage of the phrases “certainembodiments,” “some embodiments,” or other similar language, throughoutthis specification refers to the fact that a particular feature,structure, or characteristic described in connection with the embodimentmay be included in at least one embodiment of the present invention.Thus, appearances of the phrases “in certain embodiments,” “in someembodiments,” “in other embodiments,” or other similar language,throughout this specification do not necessarily all refer to the samegroup of embodiments, and the described features, structures, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Furthermore, as is consistent with the knowledge of one of ordinaryskill in the art of electronics, a controller is defined as a chip orintegrated circuit (IC) that interfaces with a peripheral device. Thus,as one of ordinary skill in the art would readily appreciate, the terms“controller” and “control IC” are interchangeable and refer to the samestructure.

As described above, in a computer system, there can be one or morecomponents that produce a large amount of heat due to a large rate ofpower consumption. For example, these components can include the CPU,the GPU, a metal-oxide-semiconductor field-effect transistor (“MOSFET”)of a VR driver, an output inductor, or a memory. To provide a securethermal design and control, it would be ideal for the computer system toalso include many temperature sensors in order to accurately sense thetemperature of each of the components that can potentially overheat. APCB pattern thermal control IC (also identified as a thermal control IC)is also necessary in order to process the input of the multipletemperature sensors. However, as the number of temperature sensorsincrease, multiple thermal control ICs are needed, as there is a limitto how many temperature sensors a single PCB pattern thermal control ICcan support. The use of multiple thermal control ICs significantlyincreases the size and cost of the PCB.

FIG. 1 illustrates a block diagram of a typical voltage regulator andcooling system for a server. The server includes a multi-core CPU(identified as “CPU” in FIG. 1), and a high speed memory, such as a dualin-line memory module (“DIMM”) (identified as “DIMM” in FIG. 1). Theserver further includes a VR multi-phase/multi-rail pulse-widthmodulation (“PWM”) control IC (identified as “VR PWM Controller”)configured to regulate the voltage of the CPU and the DIMM. In a hightask operation, the CPU and DIMM can consume power at a high rate andgenerate a high amount of heat. The server also includes temperaturesensors, such as thermistors or diodes (identified as “TH1”, “TH2”,“TH3”, and “TH4” in FIG. 1) configured to monitor the temperature ofthermal critical devices. In FIG. 1, the thermal critical devices arethe CPU (monitored by TH2), the DIMM (monitored by TH4), the driver ofthe PWM controller (monitored by TH1), and the output inductor(monitored by TH3). The temperature sensors are further configured tocommunicate the monitored temperatures to the CPU and a thermal controlIC (identified as “Thermal Control IC” in FIG. 1). The server furtherincludes multiple cooling fans (identified as “Fan M1” and Fan M2″ inFIG. 1) configured to remove heat from a thermal critical device. Thethermal control IC has a fan motor control function to control themovement of the multiple cooling fans. Thus, the thermal control IC isconfigured to receive temperature sensing input from the temperaturesensors and control the operation of the multiple cooling fans based onthe received temperature sensing input.

FIG. 2 illustrates a block diagram of a typical voltage regulator andcooling system of a notebook personal computer (“NBPC”). A NBPC issimilar to a server, and has similar components to a server. However,because a NBPC generally has a more compact configuration than a server,a NPBC needs to accommodate its components and maintain a reasonableinternal temperature using a limited space as compared to a server.Similar to the server in FIG. 1, the NBPC includes a multi-core CPU(identified as “CPU” in FIG. 1). The NBPC further includes a GPU(identified as “GPU” in FIG. 2), which is coupled to the CPU via acommunication bus. Similar to the server in FIG. 1, the NBPC furtherincludes a VR multi-phase/multi-rail PWM control IC (identified as “VRPWM Controller”) configured to regulate the voltage of the CPU and theGPU.

Much like the server in FIG. 1, the NBPC also includes temperaturesensors, such as thermistors or diodes (identified as “TH1”, “TH2”,“TH3”, and “TH4” in FIG. 2) configured to monitor the temperature ofthermal critical devices. In FIG. 2, the thermal critical devices arethe CPU (monitored by TH2), the GPU (monitored by TH4), the driver ofthe PWM controller (monitored by TH1), and the output inductor(monitored by TH3). The temperature sensors are further configured tocommunicate the monitored temperatures to the CPU and a thermal controlIC (identified as “Thermal Control IC” in FIG. 2). The NBPC furtherincludes a cooling fan (identified as “Fan M” in FIG. 2) configured toremove heat from a thermal critical device. The NBPC only includes onecooling fan, as compared to the two cooling fans of the server in FIG. 1which highlights the fact that there is limited space in the NBPC, andthus the need to reduce the number of peripheral devices is greater. Thethermal control IC has a fan motor control function to control themovement of the single cooling fan.

Thus, the voltage regulator and cooling system illustrated in FIG. 1 andFIG. 2 both use a thermal control IC to sense the internal temperatureand control the operation of one or more cooling fans. As can be seen inFIG. 1 and FIG. 2, the thermal control IC is located away from the VRblock, which includes the VR PWM control IC, the VR driver, and theoutput inductor. This is because the VR block comprises many componentswhich are tightly gathered in a small area, and also because VR driversshould ideally be located as close to a thermal critical device (e.g.,CPU, GPU, DIMM) as possible. Because the thermal control IC is locatedaway from the VR block, a communication bus, such as a two-wire datacommunication bus, is used to connect the thermal control IC, the VR PWMcontrol IC, and the thermal critical device (in most cases, the CPU).The communication bus allows the thermal control IC, the VR PWM controlIC and the thermal critical device to communicate with each other, andprovide for adaptive and intelligent control of the VR and the coolingfan(s). However, the use of a bus introduced a bandwidth limitation onthe control instructions that are sent to and from the thermal controlIC and the VR PWM control IC. A longer connection path between thethermal critical device and the thermal control IC can also result inless accurate temperature measurements due to common mode noise andleakage.

FIG. 3 illustrates a typical example of an application circuitconfigured to sense temperature at multiple locations using multipletemperature sensors. The application circuit includes two thermal diodes(identified in FIG. 3 as “CPU Thermal Diode”) configured to monitor thetemperature of a thermal critical component (such as a CPU or GPU). Thethermal diodes can be located in the thermal critical component or canbe discrete diode connected transistors. The application circuit alsoincludes a digital thermometer and temperature alarm (identified in FIG.3 as “Digital Thermometer/Temperature Alarm”), where the digitalthermometer and temperature alarm are configured to measure thetemperature of the two thermal diodes. The digital thermometer andtemperature alarm can communicate over a 2-wire serial interface. Thedigital thermometer and temperature alarm is further configured to sendan alert output signal to an system management bus (“SMBus”) controller(identified in FIG. 3 as “SMBus Controller”) when an on-chip or remotetemperature exceeds a programmed limit, and is further configured tosend a thermal input to a fan control IC (identified in FIG. 3 as “FanControl Circuit”) so that the fan control IC can operate a cooling fan(identified in FIG. 3 as “Cooling Fan”) in order to reduce thetemperature within the programmed limit.

FIG. 4 illustrates a typical sensing input circuit. The sensing inputcircuit includes a remote temperature sensor (identified in FIG. 4 as“Remote Sensing Transistor). The remote temperature sensor is operatedat a constant current and produces a base-emitter voltage (V_(BE)). Thesensing input circuit is configured to measure the change inbase-emitter voltage (ΔV_(BE)) by switching the operating current of theremote temperature sensor among two related currents (identified as “I”and “N*I” in FIG. 4). To prevent ground noise interfering with themeasurement, the more negative terminal of the remote temperature sensoris biased above ground by an internal diode (identified as “Bias Diode”in FIG. 4) at a D-input. In addition, a capacitor (identified as “C1” inFIG. 4) may optionally be used as a noise filter with a maximum value of1,000 Pf.

The resulting ΔV_(BE) waveforms are passed through a low-pass filter(identified as “Low-Pass Filter” in FIG. 4) to remove noise and then toa chopper-stabilized amplifier (identified as “Amplifier” in FIG. 4).This amplifies and rectifies the waveform to produce a direct current(“DC”) voltage proportional to ΔV_(BE).

The DC voltage is then passed to an analog-to-digital converter (“ADC”)(not shown) which digitizes the voltage and produces a temperaturemeasurement. The temperature can be calculated using the followingformula:

T=ΔV _(BE) *q/(k*ln N)

T is the absolute temperature in Kelvins. K is Boltzmann's constant(i.e., 1.38E-23). q is the charge on the electron (i.e., 1.6E-19Coulombs). N is the ration of the two currents I and N*I. While thesensing input circuit does not require any calibration to null theeffect of the absolute value of V_(BE,), the sensitivity is too small.For example, when current I is equal to 10 uA and current N*I is equalto 200 uA (and thus, N is equal to 20), temperature sensitivity is only+0.26 mV/° C. A temperature sensitivity this small means that thesensing input circuit is susceptible to noise and leakage, as will bediscussed in more detail. Thus, the sensing input circuit would need aspecial PCB layout, such as the connection between the temperaturesensor and the temperature control IC being as close as possible, or anadditional component such as a twist pair line or guard ring, in orderto mitigate the noise and leakage.

Furthermore, as described above, to provide a secure thermal design andcontrol, it is ideal for the computer system to include multipletemperature sensors in order to accurately sense the temperature of eachof the components that can potentially overheat. However, as the numberof temperature sensors increase, multiple thermal control ICs are neededbecause of a sensor and control IC connection limitation, as there is alimit to how many temperature sensors a single thermal control IC cansupport. As described above, the use of multiple thermal control ICssignificantly increases the size and cost of the PCB.

In addition, the use of multiple temperature sensors and multiplethermal control ICs increase the likelihood of increased connectionlength between a temperature sensor and a thermal control IC. This alsoposes a problem as increased connection length can increase an error inmeasured temperatures by a thermal control IC, as discussed below inrelation to FIGS. 5 and 6.

FIG. 5 illustrates a chart which correlates a common mode noisefrequency amount with a temperature sensing error amount. Inelectronics, noise is any unwanted disturbance to a desired signal. Thelonger a signal has to travel to reach a destination, the more likelythe signal can be disturbed by noise. FIG. 5 shows that noisedisturbance can cause a temperature error in the measured temperature ofa critical thermal component. For example, at 50 mV, FIG. 5 shows that acommon-mode noise at a frequency of 200 MHz causes a temperature errorof −5° C. Thus, a shorter connection between a temperature sensor and athermal control IC reduces the likelihood of a significant temperatureerror through reduction of common-mode noise.

FIG. 6 illustrates a chart which correlates a leakage resistance amountwith a temperature sensing error amount. In electronics, leakage refersto current which leaks out of a circuit. Leakage of this type can bemeasured by observing that a current flow at a first point does notmatch the current flow at the second point. This mismatch of currentflow indicates that current is leaking out of the circuit between thefirst point and the second point. Leakage resistance is electricalresistance that opposes the current which leaks out of the circuit. Inother words, the higher the leakage resistance, the smaller the currentamount leaking from the circuit. Likewise, the lower the leakageresistance, the greater the current amount leaking from the circuit. Thelonger a signal has to travel to reach a destination, the more likelythat the signal will suffer from leakage, subject to the leakageresistance. FIG. 6 shows that the lower the leakage resistance (i.e.,the higher the leakage) is, the higher a resulting temperature error inthe measured temperature of a critical thermal component is. Forexample, a 5 Mohm leakage resistance between D+ and V_(cc) results in atemperature error of 5° C. Thus, a shorter connection between atemperature sensor and a thermal control IC reduces the likelihood of asignificant temperature error, through reduction of leakage.

According to an embodiment of the invention, a microprocessor-basedcontrol IC is provided which includes a VR controller, multipletemperature sensors, and a cooling fan motor controller in a singlecircuit. In the embodiment, the output power of the VR is adaptivelycontrolled by a microprocessor using monitored temperature informationand cooling fan motor control information. As one of ordinary skill inthe art would readily appreciate, “adaptively” refers to the ability toadapt, or change behavior, in response to a specific scenario. Thus,according to an embodiment of the invention, the output power of the VRis increased or decreased in response to the monitored temperatureinformation and cooling fan motor control information. In theembodiment, the problems of multiple thermal control ICs and longerconnections between a temperature sensor and a thermal control IC can bereduced, and a low cost solution can be provided, as will be describedin more detail.

FIG. 7 illustrates a microcontroller unit-based VR and cooling controlIC, according to an embodiment of the invention. In the illustratedembodiment, the VR and cooling control IC includes three blocks: asystem block, a CPU block, and a peripheral block (identified as “SystemBlock,” “CPU Block,” and “Peripheral Block” in FIG. 7, respectively).

In the embodiment, the system block includes an oscillator (identifiedas “PLL,” “HOCO”, and “LOCO” in FIG. 7), a V_(cc) level monitor(identified as “LVD” and “VDC” in FIG. 7), and a clock generator(identified as “CPG,” and “WDT” in FIG. 7).

The oscillator is a circuit configured to produce a repetitiveelectronic signal (also identified as a “clock signal”). This clocksignal can be used to synchronize operations in a digital circuit. Forexample, the oscillator can be a harmonic oscillator configured toproduce a sinusoidal output signal, or a relaxation oscillatorconfigured to produce a non-sinusoidal output signal, such as a squarewave or saw tooth wave. According to the embodiment, the oscillator caninclude a phase-locked loop (“PLL”) which is a control system thatgenerates a signal that has a fixed relation to a phase of a referencesignal. The oscillator can also include a high-speed on-chip oscillator(“HOCO”). The oscillator can also include a low-speed on-chip oscillator(“LOCO”). The oscillator can either use the HOCO or the LOCO to producethe clock signal that the oscillator sends to the CPU or other componentof the VR and cooling control IC. While both the HOCO and the LOCO arecapable of producing a clock signal to synchronize operations in the VRand cooling control IC, the HOCO provides the clock signal at a higherfrequency than the LOCO.

The V_(cc) level monitor is a monitor configured to monitor a level of asupply voltage (“V_(cc)”) of the VR and cooling control IC. The supplyvoltage is the voltage provided by a power supply terminal of the IC.According to the embodiment, the V_(cc) level monitor can include a lowvoltage detector (“LVD”) which is configured to detect when the V_(cc)drops below a predetermined level. The V_(cc) level monitor can alsoinclude a voltage down converter (“VDC”). The VDC is a circuitconfigured to step down supply voltage provided by a power supplyterminal of the IC to an internal operation voltage of the IC.

The clock generator is a circuit configured to produce a timing signal(identified as a “clock signal”) that is used to synchronize theoperation of the VR and cooling control IC. The clock signal oscillatesbetween a high state and a low state and is utilized like a metronome tocoordinate the action of a circuit. The timing signal can be, forexample, a symmetrical square wave, or other more complex arrangements.According to the embodiment, the clock generator can include a clockpulse generator (“CPG”) which is configured to generate a pulse used forthe clock signal. The clock generator can further include a watchdogtimer (“WDT”) which is configured to determine when a program run on theVR and cooling control IC, and trigger a system reset of the VR andcooling control IC.

In the embodiment, the CPU block includes a memory and interface (“IF”)(identified as “Flash,” “Flash IF,” “SRAM,” SRAM IF,” and “CPU Bus” inFIG. 7), a CPU kernel (identified as “CPU kernel” in FIG. 7), and aperipheral block interface (identified as “PBIF” in FIG. 7).

The memory is a computer data storage configured to store digital data.In the embodiment, the memory includes a flash memory which is anon-volatile computer data storage that can be electronically erased andreprogrammed where data is retained even when no power is provided tothe flash memory. In the embodiment, the memory also includes a staticrandom access memory (“SRAM”), which is a computer data storageconfigured to store digital data using a bistable latching circuit,where the SRAM allows the data to be accessed in any order, and wherethe SRAM does not need to be periodically refreshed.

While the illustrated embodiment in FIG. 7 shows that the memoryincludes a flash memory and a SRAM, one of ordinary skill in the artwould readily appreciate that the memory may include any kind ofcomputer data storage known to one of ordinary skill in the relevantart, and still be within the scope of the invention.

The interface is configured to allow the memory to communicate with therest of the VR and cooling control IC. In the illustrated embodiment,the flash interface (identified as “Flash IF” in FIG. 7) allows theflash memory to communicate with the rest of the VR and cooling controlIC, and the SRAM interface (identified as “SRAM IF” in FIG. 7) allowsthe SRAM to communicate with the rest of the VR and cooling control IC.

According to the embodiment, the arithmetic calculator unit includes theCPU kernel, which is the portion of a computer system that is configuredto carry out instructions of a computer program and is the primaryelement for carrying out a computer system's functions. The CPU kernelis also configured to receive and transceiver temperature data and PWMwaveforms to and from different components of the microcontrollerunit-based VR and cooling control IC.

The peripheral block interface is configured to allow the components ofthe system block and the CPU block to communicate with the components ofthe peripheral block.

In the embodiment, the peripheral block includes timers (identified as“Timer 8 bit,” “Timer 16 bit 2 ch,” and “PWM 8 bit 8 ch,” in FIG. 7), aserial interface (identified as “Serial I/F (PMBus),” and “SVID” in FIG.7), and an analog interface (identified as “Comparator,” “ADC+SW,” and“DAC+PSC,” in FIG. 7).

A timer is a digital counter configured to either increment or decrementat a fixed frequency, which is configurable. A timer is also configuredto compare its timer value against a specific value, and trigger anaction when its timer value matches the specific value. In theembodiment, the timers illustrated in FIG. 7 can include an 8 bit timer(identified as “Timer 8 bit” in FIG. 7), a 16 bit timer (identified as“Timer 16 bit 2 ch” in FIG. 7), and a PWM timer (identified as “PWM 8bit 8 ch” in FIG. 7). The 8 bit timer, the 16 bit timer, and the PWMtimer can be used to generate a PWM signal.

The serial interface is configured to communicate with other componentsof the communication system by sending and receiving data one bit at atime. Thus, the serial interface is configured to send and receive adata stream. In the embodiment, the serial interface can include aserial interface configured to communicate with a power converter orother power system device, such as a PMBus (identified as “Serial I/F(PMBus)” in FIG. 7). The serial interface can also include a serialvoltage identification digital (“SVID”) interface (identified as “SVID”in FIG. 7). The SVID is configured to send and receive serial VIDsignals.

The analog interface is configured to interface with an analog signal.For example the analog interface can interface with a voltage orcurrent. The analog signal connects through a bonding pad (“PAD”)(identified as “PAD” in FIG. 7) to an IC pin (not shown).

In the embodiment, the analog interface can include a comparator(identified as “Comparator” in FIG. 7). A comparator is configured tocompare two voltage or currents and determine which voltage or currentis larger. In the embodiment, the analog interface can also include anADC and a switch (identified as “ADC+SW” in FIG. 7). The ADC and switchcircuit are configured for multiple temperature sensor input, and thePWM generator is configured for fan motor control, as will be describedin more detail in relation to FIG. 8. In the embodiment, the analoginterface can also include a digital-to-analog converter (“DAC”), and aPower SiP Controller (“PSC”) (identified as “DAC+PSC”) in FIG. 7). TheDAC and PSC are configured for VR control, as will be described in moredetail in relation to FIG. 9.

FIG. 8 illustrates a temperature sensor and fan control portion of amicrocontroller unit-based control IC, according to an embodiment of theinvention. In the illustrated embodiment, the temperature sensor and fancontrol portion of the microcontroller unit-based control IC includes anADC (identified as “ADC” in FIG. 8), a bias constant current (identifiedas “IB” in FIG. 8), a calibrating sensor (identified as “S0” in FIG. 8),a matrix of temperature sensors (identified as “S1,” “S2,” “S3,” “S4,”“S5,” “S6,” “S7,” “S8,” “S9,” “S10,” “S11 ,” and “S12,” in FIG. 8), aselector row switch for the matrix of temperature sensors (identified as“SW1” in FIG. 8), a selector column switch for the matrix of temperaturesensor (identified as “SW2” in FIG. 8), two PWM controllers (identifiedas “PWM1” and “PWM2” in FIG. 8), and two cooling fan motor control ICs(identified as “Fan Motor IC 1” and “Fan Motor IC 2” in FIG. 8).

In an embodiment, each temperature sensor can use continuous connectedtaping. Continuous connected taping keeps wafer location informationfrom die pick-up to package fabrication and taping. This means thatadjacent products in the tape can be built using adjacent dies on thewafer. The V_(BE) (or Vf) of adjacent dies are matched so measured Vfand temperature information of

The operation of the temperature sensor and fan control portion of amicrocontroller unit-based control IC will now be described inaccordance with an embodiment of the invention. According to theembodiment, during an initial calibration of the microcontrollerunit-based control IC, selector row switch SW1 connects to a line whichconnects to calibration sensor S0 (identified as line “d” in FIG. 8) andmeasures the voltage generated by S0 using the ADC. This voltage isidentified as “VT-0-0,” and represents the voltage generated at a knowntemperature. For example, the voltage can represent the voltagegenerated at a predetermined temperature that is between 20° C. and 25°C. (identified as “room temperature”). The voltage VT-0-0 and the knowntemperature (identified as “T0-0”) is stored in a built-in Flashread-only memory (“ROM”) (not shown in FIG. 8) for an initialcalibration. In an embodiment, this initial calibration can be performedduring a microcontroller unit-based control IC fabrication testingprocess.

The relation between VT0-0, IB, and T0-0 is described below:

T0−0=(0.5*VT0−0*q−Eg)/ln(IB/A)

K is Boltzmann's constant (i.e., 1.38 E-23). q is the charge on theelectron (i.e., 1.6 E-19 Coulombs). Eg is a silicon band gap energy(i.e., 1.11V). A is a current constant factor described in the equation:Is=Aexp(−Eg/kT), where Is is a saturation current.

The temperature sensitivity can be represented as ΔV/ΔT=(Vf−Eg)/T. When,Vf=0.5V, T=375K, ΔV/ΔT=−1.65 mV/K. Thus, when 2*Vf=1V, T=375K ΔV/ΔT=−3.3mV/K. This is approximately 13 times larger than temperature sensitivityof previous control ICs.

Using the above formula, the microcontroller unit-based control IC candetermine a control temperature of the IC based on the voltage generatedby calibration sensor S0. According to the embodiment, themicrocontroller unit-based control IC can utilize calibration to nullifythe effect of the absolute value of V_(BE) (or Vf) by device to device.Furthermore by using a calibration sensor, the stored voltagetemperature, and a temperature sensor configured to monitor atemperature (e.g. S1), it is easy to calibrate the microcontrollerduring the power on sequence.

According to the embodiment, the microcontroller unit-based control ICis subsequently calibrated a second time. For example, themicrocontroller unit-based control IC can be calibrated a second timeupon a power on sequence of the microcontroller unit-based control IC,where power is first transmitted from a power supply to themicrocontroller unit-based control IC. During this second calibration,the ADC measures the voltage generated by calibration sensor S0(“identified as “VT0-1”) and a control temperature of the IC (“T0-1”) isdetermined using the VT0-0 and T0-0 values previously stored in theFlash ROM. In an embodiment, each temperature sensor of the matrix oftemperature sensors S1-S12 can use continuous connected taping.Continuous connected taping keeps wafer location information from diepick-up to package fabrication and taping. This means that adjacentproducts in the tap can be built using adjacent dies on the wafer. TheV_(BE) (or Vf) of adjacent dies are matched so measured Vf andtemperature information of S1 during the power on calibration can usethe other temperature sensors (i.e., S2-S12) commonly.

According to the embodiment, the ADC detects a voltage of eachtemperature sensor of the matrix of temperature sensors in order tomeasure the temperature surrounding each temperature sensor. Moreparticularly, selector row switch SW1 connects to a line which connectsa first row of the matrix of temperature sensors (identified as line “a”in FIG. 8), and selector column switch SW2 scans each line connecting toeach column of the matrix of temperature sensors (identified as lines“e,” “f,” “g,” and “h” in FIG. 8). Through this scan, the ADC measuresthe voltage of temperature sensors S1, S2, S3, and S4 (identified as“VT1-1,” “VT2-1,” “VT3-1,” and “VT4-1”).

Selector row switch SW1 then switches to a line which connects to asecond row of the matrix of temperature sensors (identified as line “b”in FIG. 8). Selector column switch SW2 then again scans each lineconnecting to each column of the matrix of temperature sensors (i.e.,“e,” “f,” “g,” and “h” in FIG. 8). However, this time, because rowswitch SW2 is connected to line b, rather than line a, selector columnswitch S2 scans the voltage of temperature sensors S5, S6, S7, and S8.Thus, based on this scan, the ADC measures the voltage of temperaturesensors S5, S6, S7, and S8 (identified as “VT5-1,” “VT6-1,” “VT7-1,” and“VT8-1”).

Selector row switch SW1 then switches to a line which connects a thirdrow of the matrix of temperature sensors (identified as line “c” in FIG.8). Selector column switch SW2 then again scans each line connecting toeach column of the matrix of temperature sensors (i.e., “e,” “f,” “g,”and “h” in FIG. 8). Based on this scan, the ADC measures the voltage oftemperature sensors S9, S10, S11, and S12 (identified as “VT9-1,”“VT10-1,” “VT11-1,” and “VT12-1”).

Using the temperature value T0-1 obtained during calibration, themicrocontroller unit-based control IC calculates a set of measuredtemperatures (identified at “T1-1,” “T2-1,” . . . “T12-1,”) based on themeasured voltage values (i.e., “VT 1-1,” “VT2-1,” . . . “VT12-1”). Thisway, the microcontroller unit-based control IC obtains twelve points oftemperature data. This temperature data is provided to PWM1 and PWM2,where PWM1 is configured to generate a PWM waveform to control Fan MotorIC 1 based on the temperature data, and where PWM 2 is configured togenerate a PWM waveform to control Fan Motor IC 2. The temperature dataand PWM waveforms are further provided to the CPU of FIG. 8 in order tocontrol output power of the VR, as will be discussed in relation to FIG.9 below in more detail.

In the illustrated embodiment, the ADC is a 10 bit ADC with a 10 bitdynamic range and 8 bit accuracy. However, one of ordinary skill in theart would readily appreciate that this is merely an example of an ADC.Likewise, in the illustrated embodiment, the IB is capable of emitting100 uA of current, but this is merely an example current. Furthermore,in the illustrated embodiment, calibrating sensor S0 is a die built-incascade connected silicon junction diode, and temperature sensors S1-S12are external silicon junction diodes configured for temperature sensing.In the illustrated embodiment, the Vf is matched due to the use ofcontinuous connected taping. However, one of ordinary skill in the artwould readily appreciate that this is merely an example, and thatcalibration sensor S0 and temperature sensors S1-S12 can be any kind ofsensor described above.

Furthermore, while in the illustrated embodiment, the microcontrollerunit-based control IC includes twelve temperature sensors, in a 3×4matrix, one of ordinary skill in the art would readily appreciate thatthe microcontroller unit-based control IC can include any number oftemperature sensors, in any configuration, and still be within the scopeof the invention. Likewise, while the microcontroller unit-based controlIC includes two PWM controllers, and two fan motor ICs in theillustrated embodiment, one of ordinary skill in the art would readilyappreciate that the microcontroller unit-based control IC can includeany number of PWM controllers and any number of fan motor ICs, with eachPWM controller controlling any number of fan motor ICs, and still bewithin the scope of the invention.

Although not shown in FIG. 8, in one embodiment of the invention,temperature sensors S1-S12 can be located near a thermal criticaldevice, such as a CPU, GPU, or memory, such as a DIMM. Also, in oneembodiment of the invention, a bias current can flow from selector rowswitch SW1 via line “a” to temperature sensor S1, to selector columnswitch SW2 via line “e” to ground.

The embodiment described above provides advantages that a ΔV_(BE) methodimplemented in a typical sensing input circuit cannot provide. Forexample, the sensitivity of a ΔV_(BE) method is approximately +0.26 mV/°C., whereas the sensitivity of a microcontroller unit-based control ICaccording to an embodiment of the invention is −3.3 mV/° C. This meansthat the microcontroller unit-based control IC has a higher noiseimmunity than the ΔV_(BE) method, as the same noise level produces asmaller deviation in temperature.

Furthermore, the microcontroller unit-based control IC according to anembodiment of the invention is also less sensitive to PCB leakage thanthe ΔV_(BE) method. Specifically, a 5 Mohm leakage resistance between arow line to Vcc will only change the bias current from 100 uA to 102 uA(IL=(12−1.4)/5 Mohm=2 uA). The ΔV_(BE) will only be 0.5 mV based on thefollowing formula:

ΔV _(BE) =kT/q ln {(IB)+(IL)/IB}=0.026 ln(102/100)=0.5 mV

Based on a sensitivity of −3.3 mV/° C., a change of voltage of 0.5 mVonly results in a temperature error of 0.15° C., which is considerablysmaller than the temperature error of a typical sensing input circuit(i.e., −5° /C.). Based on these reasons, the microcontroller unit-basedcontrol IC, according to an embodiment of the invention, is able tohandle high noise conditions generally found in a long PCB layoutpattern.

FIG. 9 illustrates a VR control portion of a microcontroller unit-basedcontrol IC and power system-in-packages (“SiPs”), according to anembodiment of the invention. In the illustrated embodiment, the VRcontrol portion of the microcontroller-based control IC includes acontrol IC (identified in FIG. 9 as “IC1”), and a plurality of powerSiPs (identified as “IC2,” “IC3,” . . . “ICn”). One of ordinary skill inthe art would readily appreciate that an embodiment may include anynumber of power SiPs and still be within the scope of the invention.

In the illustrated embodiment, as can be seen in FIG. 9, control IC IC1receives voltage V_(out1&2) (identified in FIG. 9 as “V_(out1)” and“V_(out2)” to the left of IC1). Voltage V_(out1&2) represents a voltagegenerated by a thermal critical device (such as a CPU or a GPU) that isredirected to control IC IC1. Control IC IC1 compares voltage V_(out1&2)with a target voltage generated by a DAC in order to determine a voltageerror. Control IC IC1 then transmits the voltage error and a set oftiming signals to power SiPs IC2, IC3, . . . ICn. Specifically, controlIC IC1 transmits a voltage error corresponding to V_(out1) to power SiPsIC2, IC3, . . . ICn−1, and transmits a voltage error corresponding toV_(out2) to power SiP ICn. Control IC IC1 further sends a set ofmulti-phase timing signals to power SiPs IC2, IC3, . . . ICn−1, whereeach timing signal is a different phase, and sends a single-phase timingsignal to power SiP ICn. Power SiPs IC2, IC3, . . . ICn each receive thevoltage errors and timing signals, and each generate a PWM signal andvoltage output based on the received voltage errors and timing signals.Specifically, power SiPs IC2, IC3, . . . ICn−1 collectively receive avoltage error corresponding to V_(out1) and a set of multi-phase timingsignals, where each timing signal is a different phase, and collectivelygenerate a PWM signal and voltage output V_(out) (identified in FIG. 9as “V_(out1)” to the right of IC2). Furthermore, power SiP ICn receivesa voltage error corresponding to V_(out2) and a single-phase timingsignal, and generates a PWM signal and voltage output V_(out2)(identified in FIG. 9 as “V_(out2)” to the right of ICn).

According to an embodiment, the VR control portion of a microcontrollerunit-based control IC is a scalable solution, as any number of powerSiPs can be added as needed. According to the embodiment, VR outputvoltage (and output power) is controlled in order to balance between thevoltage necessary for a thermal critical device to complete a task, andthe heat generated by a resulting voltage).

FIG. 10 illustrates a VR and cooling control method according to anembodiment of the invention. In an embodiment, the VR and coolingcontrol method can be implemented at a microcontroller unit-based VR andcooling control IC.

In order to initiate the method illustrated in FIG. 10, the VR andcooling control IC first generates an interrupt using a MCU built-intimer. After generating the interrupt, at step 1, a temperature ismeasured. The temperature may correspond to a temperature of a thermalcritical device, such as a CPU or a GPU. At step 2, it is determinedwhether the measured temperature is higher than a first threshold. Afirst threshold can be a temperature where the thermal critical devicecan overheat if operated for a significant duration of time at thetemperature. If the measured temperature is higher than the firstthreshold, the method proceeds to step 3, which is described below inmore detail. Back at step 2, if the measured temperature is not higherthan the first threshold, the method proceeds to step 4, which is alsodescribed in more detail.

At step 3, a speed of a cooling fan is determined. The cooling fan maybe a cooling fan configured to decrease the temperature of a thermalcritical device. If a speed of the cooling fan is less than a maximumspeed of the cooling fan, this means that the speed of the cooling fancan be increased in order to decrease the measured temperature below thefirst threshold. If it is determined that the speed of the cooling fanis less than the maximum speed, than the method proceeds to step 6,where the speed of the cooling fan is increased. After step 6, themethod proceeds to step 10 where the method completes. If it isdetermined that the speed of the cooling fan is not less than themaximum speed, then the method proceeds to step 7.

At step 7, it is determined whether the voltage generated by the VR canbe decreased. If the speed of the cooling fan cannot be increased,another way to decrease the temperature measured at step 1, is todecrease the voltage generated by the VR. As an example, it isdetermined if the thermal critical device can operate with a decreasedvoltage. If the thermal critical device can operate with a decreasedvoltage, then the voltage generated by the VR can be decreased. If it isdetermined that the voltage generated by the VR can be decreased, themethod proceeds to step 8. At step 8, the VR is decreased by a step,resulting in the decrease of the voltage generated by the VR. In thiscontext, a step is a unit of measurement, such as a volt. Therefore, astep can equal 5 mv, or any number of volts. Furthermore, a step is notlimited to a volt as a unit of measurement, and can be any othermeasurement for measuring voltage. The method proceeds to step 10, wherethe method completes. Back at step 7, if it is determined that thevoltage generated by the VR cannot be decreased, than the methodproceeds to step 9. At step 9, a warning is issued. The warning can be awarning that the thermal critical device is in danger of overheating,and there is no way to decrease the temperature. The method subsequentlyproceeds to step 10, where the method completes.

Back at step 4, where it was determined at step 3 that the temperaturemeasured at step 1 was not higher than a first threshold, it isdetermined whether the measured temperature is lower than a secondthreshold. A second threshold can be a temperature where there is nosignificant threat of the thermal critical device overheating, and whereit is desired to decrease the speed of the corresponding cooling fan inorder to conserve power. If the measured temperature is lower than thesecond threshold, the method proceeds to step 5. At step 5, a speed ofthe cooling fan is decreased. The method then proceeds to step 10, wherethe method completes. Back at step 4, if it is determined that themeasured temperature is not lower than a second threshold, then themethod proceeds to step 10, where the method completes.

According to embodiments of the invention, a VR controller, multipletemperature sensors, and a cooling fan controller can be provided on asingle device. Thus, the number of thermal control ICs can be reduced,even in the presence of multiple temperature sensors. This can reducethe overall size of the PCB. Furthermore, a connection length between atemperature sensor and a thermal control IC, and between a VR and acooling fan can also be reduced, which can further reduce the overallsize of the PCB, and reduce potential temperature error. Furthermore, incertain embodiments, a microcontroller unit is capable of intelligentcontrol of VR and cooling in order to provide secure operation withminimum power consumption.

One having ordinary skill in the art will readily understand that theinvention as discussed above may be practiced with steps in a differentorder, and/or with hardware elements in configurations which aredifferent than those which are disclosed. Therefore, although theinvention has been described based upon these preferred embodiments, itwould be apparent to those of skill in the art that certainmodifications, variations, and alternative constructions would beapparent, while remaining within the spirit and scope of the invention.In order to determine the metes and bounds of the invention, therefore,reference should be made to the appended claims.

1. An apparatus, comprising: an integrated circuit comprising amicroprocessor and a first temperature sensor configured to generate areference temperature signal corresponding to a temperature of themicroprocessor; and temperature sensors, wherein the temperature sensorsare configured to generate respective temperature signals correspondingto respective temperatures of components including the microprocessor,wherein the microprocessor is configured to make an external temperaturecalibration using the reference temperature signal, and wherein themicroprocessor is configured to process the temperature signals.
 2. Theapparatus of claim 1, further comprising: a cooling fan motor controllerformed on the integrated circuit and configured to control a speed of afan.
 3. The apparatus of claim 1, further comprising: a voltageregulator controller formed on the integrated circuit and configured togenerate a voltage and provide the voltage to one of the components. 4.The apparatus of claim 1, further comprising: a cooling fan motorcontroller formed on the integrated circuit; and a voltage regulatorcontroller formed on the integrated circuit, wherein the microprocessor,cooling fan motor controller, and voltage regulator controller areconfigured to cause the apparatus to control the temperature of one ofthe components using one of the temperature signals.
 5. The apparatus ofclaim 1, wherein the temperature sensors are selectively coupled to themicroprocessor via first and second switches.
 6. The apparatus of claim1, wherein the microprocessor is further configured to scan multipletemperature sensors in a known temperature condition in order tocalibrate the multiple temperature sensors.
 7. The apparatus of claim 1,further comprising a diode temperature sensor configured to generate asignal corresponding to a forwarding voltage during production testingfor subsequent calibration of the temperature sensors. 8-12. (canceled)13. A method comprising: generating a reference temperature signalcorresponding to a temperature of a microprocessor; generating aplurality of temperature signals corresponding to respectivetemperatures of components including the microprocessor; themicroprocessor processing the reference temperature signal and at leastone temperature signals to make a temperature calibration.
 14. Themethod of claim 13 further comprising a cooling fan motor controllercontrolling a speed of a fan
 15. The method of claim 13 furthercomprising a voltage regulator controller generating and providing avoltage to one of the components.
 16. The method of claim 1 furthercomprising the microprocessor scanning multiple temperature sensors in aknown temperature condition in order to calibrate the multipletemperature sensors.